Infectious Diseases Flashcards
1
Q
Mono typically causes what LAD?
A
Posterior cervical LAD
2
Q
What is used to treat rosacea?
A
Metronidazole
Localized facial erythema with/without pustules and papules
3
Q
Histoplasmosis presentations (mild to severe)
A
Mild: Pulmonary + mediastinal LAD
Severe: Hepatosplenomegaly with diffuse LAD
4
Q
Vomiting after foodborne preformed toxin occurs when?
A
Within 6 hours (not 36 hrs)
5
Q
Tinea versicolor treatment
A
Topical ketoconazole, terbinafine, selenium sulfide
6
Q
Complications of malaria
A
Children - cerebral malaria: Seizure, coma, hypoglycemia, metabolic acidosis
Adults: Jaundice, acute renal failure, acute pulmonary edema
7
Q
What are additional complications of Rocky Mountain spotted fever (RMSF)? What labs?
A
Encephalitis, pulmonary edema, bleeding, shock
Severe abdominal pain
Low platelets, hyponatremia, higher AST/ALT
8
Q
Hidradenitis suppurativa - treatment
A
Mild: Topical clindamycin
Moderate: Oral tetracyclines
Severe: TNF-a inhibitors, oral retinoids, surgical excision
9
Q
Asplenic adult patients should receive what vaccines? When should they receive them?
A
Pneumococcal (PCV20 or PCV15 + PPSV23); Hib (1 dose); Meningococcal (quad and sero B, q5years)
> =14d before or after the splenectomy
10
Q
Candidemia - treatment
A
- Empiric antifungal (typically echinocandins first-line)
- Source control
- Evaluation for metastatic infection: ophthalmic, echocardiography
11
Q
Utility of galactomannan, beta-D-glucan
A
Galactomannan: Aspergillus cell wall
Beta-D-glucan: sensitive (but not specific) for yeast infections
12
Q
Organ transplant CMV affects which organ system most? Dx? Treatment?
A
GI - colitis/enteritis with multiple large shallow ulcers- fever, malaise, vomiting, bloody diarrhea, abdominal pain
Dx gold standard is biopsy of affected organ
Atypical lymphocytes on blood smear
Treat with ganciclovir and reduction of immunosuppression
13
Q
Organ transplant herpes simplex-1 reactivation organ systems
A
Tracheobronchitis, esophagitis, pneumonia, and/or hepatitis
14
Q
What is the most common cause of purulent pericaditis?
A
S. aureus from hematogenous spread; increased risk from chronic hemodialysis
15
Q
Acute lymphangitis
A
Injection drug use inoculates skin flora into subcutaneous tissue
Sx: Tender red streaks up lymphatic channels with painful, swollen, erythematous regional lymphadnitis
16
Q
Beta-D-glucan antigen
A
Rapid indicator of possible fungal infection (e.g. Candida)
17
Q
Most common causes of catheter-related bloodstream infection (CRBSI)
A
- Coagulase-negative staph (e.g. S. epidermidis)
- S. aureus
- Enterococcus
- Candida
Draw 2 sets of blood cultures (1 from catheter, 1 from peripheral site) - differentiates contamination from true infection
18
Q
Typical acute bacterial prostatitis antibiotics
A
E coli, Proteus:
1. Fluoroquinolone
2. Bactrim
Do this for 6 weeks
19
Q
Echinococcus granulosus appears how on CT?
A
Thin-walled, septated lesions, occasionally with calcifications
Contracted from infected sheep or canines
20
Q
Pulmonary histoplasmosis - chest x-ray
A
Healed granulomas (calcified)
Hilar lymphadenopathy
21
Q
What virus can lead to toxic megacolon in immunocompromised patients?
A
CMV (cytomegalovirus colitis)
Treat with ganciclovir
22
Q
Hydatid cyst appearance on CT; treatment
A
Large cyst with “eggshell” calcification, along with daughter cysts (internal septations)
Small cysts (<5 cm): Albendazole
Large cysts: Percutaneous therapy or surgery (watch for anaphylactic shock)
23
Q
Cysticercosis - bug, location
A
Taenia solium
Cysts in brain or muscle
24
Q
Uncomplicated parapneumonic effusion vs complicated vs empyema
A
Uncomplicated: Sterile exudate
Complicated: Bacterial invasion, moderate-large fluid, flowing or loculated, pH <7.2, glucose <60, WBC >50,000, LDH >1,000
Empyema: Frank pus in pleural space; bacteria positive on Gram stain
25
26
Which bacteria for most deep puncture wounds?
1. S. aureus
2. Pseudomonas
27
Antibiotics for anaerobic lung abscess
Zosyn
Carbapenem
Clindamycin (if beta-lactam allergy due to C diff risk)
28
Sydenham chorea - signs, tests
Chorea, hypotonia, behavioral changes
Motor and psychiatric symptoms tend to wax/wane
Disappear during sleep
Group A strep testing + antistreptolysin O and anti-DNAse B titers
29
What evaluation should all patients with bacterial meningitis receive before discharge?
Audiologic testing for hearing deficits - can result from inflammatory damage to cochlea
Cochlear ossification from fibrosis makes implantation surgery more difficult and outcomes poorer
30
Invasive pulmonary aspergillosis treatment
Voriconazole iv 1-2 weeks + caspofungin (an echinocandin), then prolonged oral voriconazole
31
Chikungunya - notable symptoms
Severe polyarthralgia (beginning in feet and hands) - Up to 70% develop chronic arthralgia/arthritis that lasts months/years - may require methotrexate
High fever, maculopapular rash, conjunctivitis
Lymphopenia, thrombocytopenia, transaminitis
32
Molluscum contagiosum treatments
1. Cryotherapy
2. Curettage
3. Topical (eg cantharidin)
33
Type of infection based on time since transplant
<1 month: bacterial infection from surgery
1-6 months: opportunistic infections
>6 months: typical community acquired pathogens
34
Disseminated histoplasmosis treatment
IV amphotericin B (fungicidal) 1-2 weeks, then itraconazole (fungistatic) 1 year
35
JC virus on CT brain
Nonenhancing, asymmetric, white matter lessons without edema
36
Granuloma with narrow-based budding yeast
Histoplasmosis
(Coccidioidomycosis would be spherules with endospores, unilateral lung)
37
Candidal onychomycosis is least frequent in which part?
Toenails - most likely Trichophyton rubrum
38
High-dose iv acyclovir concerns
Poor urine solubility, crystal formation in renal tubules and AKI
Give iv fluids and loop diuretic to flush
39
When is clindamycin used in context of pulmonary ID?
Anaerobes or penicillin allergy with lung abscess or aspiration pneumonia
40
AIDS esophageal infection - organisms and management
1. Candida - mild pain and concurrent oral thrush - oral fluconazole
2. HSV - well-circumscribed lesions with round/ovoid, "volcano-like" appearance, and ballooning degeneration and eosinophilic intranuclear inclusions - acyclovir
3. CMV - large, linear ulcerations in distal esophagus with intranuclear/intracytoplasmic inclusions - ganciclovir
41
42
Is HIV adenopathy painful or not?
Not painful, unlike mono
43
Rat-bite fever
Flu-like illness with diffuse maculopapular rash and arthralgia
44
Q fever
Tick-borne Coxiella burnetii, pleomorphic rod
Prolonged flu-like illness
Maculopapular rash
45
What else is transmitted by scratch besides Bartonella?
Pasteurella multocida - both are gram-negative coccobacilli
Bartonella causes papule and tender lymphadenopathy
Pasteurella causes cellulitis and lymphangitis
46
Tularemia vs others
Tularemia has ULCERATING papule with central eschar and tender regional lymphadenitis
Sporothrix may ulcerate but is not painful
47
Does Q fever produce lymphadenopathy?
No
48
Does rat bite fever cause lymphadenopathy?
No
49
Hep C - extrahepatic manifestations
Derm: Porphyria cutanea tarda, lichen planus
Renal: Membranoproliferative glomerulonephritis
Hematologic: Mixed cryoglobulinemia, ITP, AIHA
50
Isoniazid heme concern
Pyridoxine antagonist -> acquired sideroblastic anemia presenting as microcytic hypochromic anemia (dimorphic RBCs)
Unlike IDA, iron and TIBC may be normal or other direction
Give pyridoxine
51
Causes of false positive nontreponemal test
Pregnancy, HIV, IV drug use, liver disease, autoimmune
52
What infection can lead to toxic epidermal necrolysis
Mycoplasma pneumoniae
53
Bed bugs vs scabies
Bed bugs: linear tracks in exposed areas; palms not involved since skin too thick
Scabies: extensive excoriations and linear burrows, involves palm and web spaces, flexor wrists and extensor elbows, can develop pustules and wheals
54
Scabies treatment
5% permethrin or oral ivermectin
55
Hyphae and yeast in spaghetti and meatballs pattern
KOH prep of tinea versicolor
56
Tinea versicolor treatment
Topical ketoconazole, terbinafine, or selenium sulfide
Caused by Malassezia
Often hypopigmented if after sun exposure (which pathologizes this commensal bacteria) due to darkening of surrounding skin
57
Sporothrix treatment
Prolonged itraconazole
58
Cigar-shaped yeast with narrow-based budding at 37 C
Sporothrix, a dimorphic fungus from decaying plants/soil
59
Whipple disease - manifestation
Chronic malabsorptive diarrhea (steatorrhea, flatulence, distention)
Protein-losing enteropathy
Weight loss
Migratory non-deforming arthritis
LAD
Low-grade fever
60
Whipple disease - diagnosis
Small intestinal biopsy and PCR
PAS stain positive macrophages in lamina propria with non-acid-fast Gram+ bacilli
61
Aspergillus appearance on X-ray
Cavitary mass with air crescents at periphery
62
Infective endocarditis risk due to prosthetic valve, cardiac graft, or certain congenital cyanotic heart disease - which prophylactic antibiotics
Dental, respiratory: oral amoxicillin (reduce Strep viridans)
GU/GI procedure with active infection: oral amoxicillin (reduce Enterococcus)
SST procedure with active infection: IV vancomycin
63
Erythematous edematous lesion -> bulla surrounded by erythema -> rupture -> painless ulcer with black center
Ecthyma gangrenosum = Pseudomonas
Often seen in immunocompromised state
64
Who should not receive Varicella vaccine?
This is a live vaccine - do not give if CD4 <200
Zoster (shingles) vaccine, however, can be given to HIV patients
65
Viral infection is more likely to cause what kind of cardiomyopathy?
Dilated cardiomyopathy
66
Small hemorrhagic lesions on retina with white centers
Roth spots, highly suggestive of infective endocarditis
67
Most common causes of osteomyelitis in SCD
Salmonella
S aureus
Otherwise, Strep pneumo is most likely to cause bacteremia/sepsis, often with no identifiable source
68
Vesicles on posterior oropharynx
Herpangina from coxsackievirus A
Erythematous papules -> gray vesicles and ulcers
Coxsackie can also present as hand-foot-mouth disease with additional papules on palms and soles
Coxsackie can cause encephalitis
69
Can impetigo cause rheumatic fever?
No, but it can cause APSGN
70
CD4 counts for CMV, Cryptococcus, Toxoplasma
CMV: 50
Cryptococcus: 100
Toxoplasma: 100
71
Vitamin A decreases morbidity/mortality of what infection?
Measles
72
HHV-6 symptoms
Roseola - blanching maculopaular rash starting trunk then everywhere else; follows febrile phase
73
Lyme arthritis (late manifestation) - characteristics
Large effusion but minimally painful, 10,000-25,000 leukocytes, negative Gram stain and culture
74
Lyme arthritis (late manifestation) - characteristics
Large effusion but minimally painful, 10,000-25,000 leukocytes, negative Gram stain and culture
75
Chlamydia arthritis vs Gonorrhea vs Lyme arthritis
Chlamydia is asymmetric oligoarthritis with urethral and eye manifestations
Gonorrhea starts with acute monoarthritis but becomes oligoarthralgia, quite painful, typically >25,000 leukocytes mostly neutrophils
Lyme is monoarticular, minimally painful arthritis, 10,000-25,000 leukocytes, negative Gram and culture
76
Link the following infective endocarditis bugs:
S aureus
S epidermidis
Strep viridans
S Strep gallolyticus
Enterococcus
Fungi
S aureus - Prosthetic valves, catheters, implanted devices, IV drugs
S epidermidis - same but not IV drugs
Strep viridans (mutans, mitis, oralis, sanguinis) - Gingival manipulation, respiratory tract incision/biopsy
Strep gallolyticus - Colon cancer, IBD
Enterococcus - Nosocomial UTI
Fungi - Immunocompromised, IV catheter, prolonged antibiotics
77
Lyme meningitis from dissemination is what predominance?
Lymphocytes
78
Central hemorrhagic punctum bite
Bedbugs - confirmation requires visualization
79
Where can Histoplasma disseminate?
Reticulonodular infiltrates with hilar or mediastinal LAD -> hepatosplenomegaly, LAD -> pancytopenia
Adrenal infiltration can occur in minority of cases
80
C diff risk factors
1. Antibiotics
2. Hospitalization
3. IBD
81
Solitary vs multiple irregular, ring-enhancing lesion in brain of AIDS patient CD4 <50
Solitary: CNS lymphoma - EBV DNA in CSF basically confirms
Multiple: more likely toxoplasmosis
82
Postherpetic neuralgia vs acute/subacute pain management
Acute (<=30days from rash) and subacute (30d - 3mo) - treat with NSAIDs, analgesics
Postherpetic (>3mo): treat with gabapentin, pregabalin, or TCAs
83
Tinea appearance on microscopy
Branched, segmented hyphae
84
Purpose of Wood’s lamp examination
Assess for microsporum infection in setting of tinea capitis
85
Prophylaxis for possible Hep B exposure if titers low (anti-HBsAg titer <10) and no history of previous or current infection
HepB Ig and vaccine
86
Do bed bugs affect genitalia?
No, typically only exposed areas
Corticosteroids can help with itching
87
Why is Bactrim not used for Gram+?
High rates of Strep resistance
88
What frequency of severe HSV requires daily antiviral?
>6 outbreaks per year
89
Impetigo treatment
Mild - mupirocin
Severe (non-MRSA) or ecthyma - oral cephalexin, dicloxacillin
Severe (MRSA) - clindamycin, doxycycline, bactrim
SSSS - nafcillin, vancomycin, wound care
90
Small pink papules on trunk + fever, GI
Salmonella typhi - rose spots
91
Erysipelas usually caused by... How does it differ from other cellulitis?
GAS; raised, indurated, well-demarcated
92
Folliculitis resistant to therapy and intensely pruritic
Suspect eosinophilic folliculitis 2/2 AIDS; would need biopsy
93
Isotretinoin requires what monitoring?
Elevates LFTs; teratogen
Liver function, cholesterol, triglycerides, baseline and serial pregnancy tests
94
Are antibiotics needed for pilonidal cysts?
Not unless cellulitis - would need aerobic and anaerobic coverage
95
Leprosy treatment
Tuberculoid: dapsone + rifampin
Lepromatous: add clofazimine
96
C diff treatment for fulminant +/- ileus
PO vanc + parenteral metronidazole
Rectal vanc an option if ileus
97
Echinococcus - treatment
Surgical resection of cysts and albendazole
98
Entamoeba histolytica - treatment
Metronidazole
99
Triad of myositis, periorbital edema, and eosinophilia
Trichinella spiralis - treat with albendazole (and steroids if severe)
100
Ethambutol adverse effect
Optic neuritis
101
Isoniazid adverse effects
Hepatitis
Peripheral neuropathy (give pyridoxine)
102
MAC - treatment
Macrolide + ethambutol +/- rifabutin
103
Anthrax treatment
Inhalational or head/neck areas: Ciprofloxacin or doxycycline + 1-2 additional antibiotics for at least 14 days
Other skin: 7-10 days
Postexposure prophylaxis woth ciprofloxacin for 60 days
104
Organisms to worry about based on hand bite
Dogs and cats: Pasteurella, Staph, Strep
Human: Eikenella, GAS
105
What antibiotics added for prosthetic IE?
+/- gentamicin, rifampin
Oxacillin or nafcillin for MSSA, vanc for MRSA
106
What infection can cause Vit B12 deficiency?
Fish tapeworm, Diphyllobothrium latum
107
Pupils constrict to accommodation but not light
Argyll Robertson pupils - tertiary syphilis
108
Syphilis treatment if neurosyphilis confirmed from LP
IV penicillin x14 days (as opposed to IM x1 for early latent or IM weekly x3 for late latent)
109
Klebsiella granulomatis - treatment
Azithromycin or doxycycline
110
H ducreyi (chancroid) treatment
Azithromycin or ceftriaxone x1
111
Lyme encephalitis vs RMSF or ehrlichiosis treatment
Lyme encephalitis is ceftriaxone; others are doxycycline
112
What drug to avoid in HIV-associated dementia?
Efavirenz - due to CNS side effects
113
Toxic shock syndrome treatment
MSSA: Clindamycin (for antitoxin properties) + nafcillin or oxcillin
MRSA: Clindamycin + vancomycin
114
Primaquine - when to use for malaria
P ovale or P vivax infections, or unknown - eradicate hypnozoites in liver
115
Does malaria cause rash?
No
116
Mosquito-borne virus differential
All three of these have rash, fever, myalgia:
Chikungunya: joint pain
Dengue: bone pain, bleeding/shock
Zika: conjunctivitis, headache, GBS
117
Lyme treatment; prophylaxis guidelines
Doxycycline, amoxicillin if pregnant, ceftriaxone if disseminated
Ppx: 1 dose doxycycline if tick >=36 hr, ppx <72 hr after removal, endemic >20%, and no contraindications
118
Babesiosis vs Lyme
Intravascular hemolysis, jaundice, anemia
Maltese cross
IV azithromycin + atovaquone
119
RMSF treatment
Doxycycline; if pregnant, chloramphenical during 1st two trimesters, otherwise doxycycline
120
Ehrlichiosis vs other tick diseases
Headache, fever, chills, AMS, myalgia - but no rash
Use doxycycline
121
Special HIV testing conditions
Early acute HIV: need combination test (HIV1/2 antibodies + p24) + viral RNA load (PCR-RNA)
Perinatal: Use NAAT to avoid confusion with maternal Ab
122
Oval yeast cells in macrophages in HIV
Histoplasma
123
Histoplasmosis ppx in HIV CD4 <150
Itraconazole
124
Zidovudine - adverse effects
Bone marrow suppression, megaloblastic anemia
125
One clinical scenario for efavirenz
NNRTI - doesn't interfere with TB meds
Teratogenic, hepatotoxic, rash or SJS
126
Maraviroc vs enfuvirtide
Maraviroc blocks gp120 docking protein
Enfuvirtide blocks gp41 fusion protein
127
Boosting agents in HIV
Cobicistat and the protease inhibitors ritonavir, saquinavir
Inhibit CYP3A to increase drug levels of others
128
Rabies post-exposure ppx
Previously immunized: vaccine only
Never immunized: vaccine + rabies Ig
129
Partially acid-fast, filamentous, branching rods; pneumonia, brain abscess immunocompromised host
Nocardia
Treat with bactrim; add amikacin if disseminated; carbapenems if brain involved
130
Pneumocystis treatment if sulfa allergy
Clindamycin + primaquine
131
Cryptosporidium treatment in immunocompromised
Nitazoxanide
132
Giardiasis treatment
Tinidazole or nitazoxanide
Children can use metronidazole as alternative
Paromomycin in 1st trimester
133
Entamoeba treatment
Metronidazole or tinidazole + paromomycin
